The state of the art includes various types of taps for sanitation articles, with different shapes and sizes, wherein the water is mixed in a mixer assembly or mixer cartridge, mounted inside a central metallic body and commanded by a single lever suitable to rotate both on a vertical and horizontal plane.
Taps with the command lever arranged on the upper part are very common: they are very easy for the user to operate. In taps such as these the command lever is displaced up or down to open or close the delivery of water, or to regulate the flow, and towards the left or right to mix the hot and cold water so as to obtain the suitable temperature.
The terminal ends of the hot and cold water feeder pipes are connected to the lower part of the mixer assembly, also one end of the outlet or delivery pipe which, by means of a flexible element, terminates on the outlet mouth of the tap.
In taps such as are known in the state of the art, a non-return return valve is inserted in each water feeder pipe, outside the mixer assembly and very far therefrom. This creates problems for those who install and maintain the taps, since it is very inconvenient to access the points where the valves are located.
Moreover, in taps such as are known in the state of the art, some parts of the taps which are in contact with the water are made of metallic alloys, such as brass, which also contain lead, even though in small quantities.
This is a considerable disadvantage, as lead is an element which is considered highly cancerogenous and therefore to be avoided, to the extent that in some countries there are legal restrictions, like the NSF 61 standard in the USA, which limit the presence of lead to extremely low percentages.
The present Applicant has designed and embodied this invention to overcome these shortcomings and to obtain further advantages.